Brain serotonin determines maternal behavior and offspring survival.

Area of Science:

• Neuroscience
• Behavioral Biology
• Genetics

Background:

• Maternal care is essential for mammalian offspring survival and development.
• Serotonergic pathways in the brain regulate maternal behaviors, but their specific role is poorly understood.

Purpose of the Study:

• To investigate the contribution of brain serotonin to maternal care using mice genetically deficient in serotonin.
• To assess the impact of serotonin depletion on various maternal behaviors and offspring outcomes.

Main Methods:

• Utilized mice with a null mutation in the tryptophan hydroxylase-2 (TPH2) gene, leading to brain serotonin depletion.
• Evaluated maternal behaviors (pup retrieval, huddling, nest building, nursing) and offspring parameters (survival, weight, cannibalization) in TPH2(-/-) dams.
• Employed cross-fostering and mixed-genotype litter paradigms to differentiate genetic and environmental influences.

Main Results:

• TPH2(-/-) mothers exhibited reduced offspring survival, lower weaning weights, and increased cannibalization.
• Impaired maternal behaviors included poor pup retrieval, huddling, nest construction, and nursing.
• Deficits in TPH2(-/-) pups were rescued by cross-fostering, but TPH2(-/-) dams showed persistent behavioral deficits.
• TPH2(-/-) pups negatively impacted maternal behavior in wild-type dams, increasing cannibalism and attack latency.

Conclusions:

• Brain serotonin, regulated by TPH2, profoundly influences nearly all aspects of maternal behavior.
• Serotonin depletion in dams leads to maladaptive maternal care and compromised offspring development.
• TPH2(-/-) pups can induce poor maternal behavior in dams of both genotypes, suggesting complex mother-infant interactions.